A United Nations official today described the coastal strip housing thousands of civilians in northern Sri Lanka as a "killing field", with unattributed UN sources putting the death toll there at up to 8,000 since January, dpa reported. Officials in Geneva said pleas to the Sri Lankan government and the Tamil Tiger rebels for access to the conflict zone for humanitarian and to allow refugees to flee have gone unheeded, while thousands have been killed in recent months. Rupert Colville, a spokesman for the High Commissioner for Human Rights, called for an independent committee to investigate possible war crimes, and said the supposed safe zone on a northern beach "could turn into a killing field, if it is not already one." Calls for the two sides to the conflict to respect the laws of war have also been "consistently ignored," the UN Office for the Coordination of Humanitarian Affairs (OCHA) said in Geneva. UN officials, speaking with the German Press Agency dpa on condition of anonymity, have given "conservative" estimates that 7,000 and even possibly 8,000 people have been killed since the end of January Speaking in the British parliament this week, Bill Rammell, a junior Foreign Office minister, said 6,500 civilians had been killed, and if accurate, the reports were "appalling." He was apparently basing his statistics on an internal note that was at least several days old. Journalists and aid workers are prevented by the government from gaining access to the conflict zone. Somewhwere between 20,000 civilians, according to the government, and 50,000, according to UN agencies, are trapped in a tiny rebel- held enclave in the north. The scenes in the small coastal enclave in north-east Sri Lanka has been described by the International Committee of the Red Cross as an "unimaginable humanitarian catastrophe." Other UN senior officials, including John Holmes, the top humanitarian affairs coordinator, have warned of a "bloodbath."